|NWRA Research Information|
This page is in the process of being developed and managed by NWRA’s Research Committee.
To view/share a copy of the Research brochure, click here.
Research Committee Purpose
To encourage and support post-release studies of rehabilitated wildlife and the wide dissemination of the information that is gained from such studies.
The Need for Research
NWRA encourages and supports wildlife rehabilitation organizations in conducting independent and/or collaborative research projects. Post-release studies are vital for determining post-release survival, dispersal, reproductive success, and behavior of rehabilitated wildlife. Such studies also offer an opportunity to evaluate and compare the successfulness of varying approaches utilized in modern rehabilitation practices. Wildlife rehabilitation is a young science and frequently is criticized for its lack of quantitative evidence describing survivorship, behavioral responses, and overall reproductive fitness of rehabilitated wildlife following release. Successfully completed post-release studies are needed to bridge the gap to improve wildlife rehabilitation techniques, to allow for continued growth within the profession, and to further contribute to scientific knowledge.
Goals of the NWRA Research Committee
Individuals with questions or an interest in working on this committee can contact the NWRA research committee chair: January Bill at JanuaryBill@hotmail.com.
NWRA Funded Research & Education Grants
The National Wildlife Rehabilitators Association Grants Program awards research grants in the field of wildlife rehabilitation, including wildlife medicine and wildlife education. Proposals funded in past years are listed below, along with publication citations in which research or study results are reported.
The following is a selected list of post-release papers resulting from grants awarded by the NWRA:
The committee is in the process of compiling post-release study papers for reference by species. Papers listed below are taken from the Annotated Bibliography of Wildlife Rehabilitation, 2nd edition Volumes 1 – 18, 1982 – 2000.
Boughner, G. 1995. Post-release Observations of Captive-reared American Kestrels (Falco sparverius). (D. R. Ludwig, editor). Pp. 139-152 in Wildlife Rehabilitation, Vol. 13. National Wildlife Rehabilitators Association: St. Cloud, MN.
Abstract: There is growing interest in rehabilitating birds of prey that have been injured or orphaned, often as a direct result of human contact. Little is known of the ultimate fate of these birds after release. In this 2-year study, 4 wild-reared and 15 captive-reared young American kestrels (Falco sparverius) were studied using radiotelementry. Results suggest that rehabilitated kestrels can be returned successfully to the wild.
Clumpner, C., & J. Wasserman. 1991. Rehabilitation of Orphaned and Injured Black Bear Cubs, (Ursus americanus). (D. R. Ludwig, editor). Pp. 35-40 in Wildlife Rehabilitation, Vol. 9. National Wildlife Rehabilitators Association: St. Cloud, MN.
Introduction: The American black bear (Ursus americanus), the only truly native bear of North America, is classified as a carnivore but gastronomically and morphologically is an omnivore. The black bear’s size, teeth and claws, and reputation require a number of special considerations for wildlife rehabilitators. Many state wildlife agencies would prefer that rehabilitators not work with large mammals, citing danger to the public from animals habituated to people and large and strong enough to severely injure or kill a human. Some states prohibit the release of rehabilitated bears, cougars, and deer. If members of these species are reared and rehabilitated, it is extremely important that it be done correctly and success documented with post-release studies. This paper details the rehabilitation, release, and post-release radio tracking of one bear by HOWL Wildlife Rehabilitation Center. Rehabilitation techniques successfully used in the rehabilitation of black bears are discussed.
Convy, J. A., & M. Zaremba. 1998. Post-release Survival and Movements of Captive-reared Bobcats (Felis rufus). (D. R. Ludwig, editor). Pp. 115-122 in Wildlife Rehabilitation Vol. 16. National Wildlife Rehabilitators Association: St. Cloud, MN.
Case study of two bobcats rehabilitated in Washington State.
Daniels, J. 1984. A Post-release Telemetry Study of the Barn Owl. (P. Beaver, editor) Pp. 163-169 in Wildlife Rehabilitation, Vol. 3. National Wildlife Rehabilitators Association: St. Cloud, MN.
Introduction: The purpose of this study was to observe the behavior of two radio-tagged juvenile Barn Owls (Tyto alba practincola) before and after release. During the pre-release training, hacking, and post-release periods the methods being used were evaluated for future reference.
Fitzpatrick, J. M. 1985. Bald Eagle Telemetry: Report on Results of the First NWRA Grant. (P. Beaver, editor). Pp. 124-128 in Wildlife Rehabilitation, Vol. 4. National Wildlife Rehabilitators Association: St. Cloud, MN.
Introduction: In 1984 the National Wildlife Rehabilitators Association (NWRA) announced the awarding of its first major grant to further knowledge about wildlife rehabilitation. A one thousand dollar grant was awarded to the Carpenter St. Croix Valley Nature Center (CNC) for a post-release radio telemetry study of bald eagles (Haliaeetus leucocephalus). The birds to be studied were rehabilitated through the combined efforts of the Raptor Research and Rehabilitation Project of the School of Veterinary Medicine of the University of Minnesota (RRRP) and the CNC. The objectives of the grant proposal read as follows:
Heinrich, G. 1987. Ramifications of Releasing/Relocating Reptiles and Amphibians and Subsequent Effects Upon The Existing Herpetofaunal Community, With Techniques and Guides For Improving Success Rates. (D. J. Mackey, editor). Pp. 105-114 in Wildlife Rehabilitation, Vol. 6. National Wildlife Rehabilitators Association; St. Cloud, MN.
Abstract: Problems associated with the release and relocation of reptiles and amphibians are discussed. Consequences of both accidental and intentional release of herpetofaunal species are examined. A discussion on habitat components and species requirements offers assistance in the selection of release and relocation sites. Techniques and guidelines are offered for improving success rates of release and relocation program.
Kimmel, F., & P. J. Zwank. 1983. Post-release Survivorship, Dispersal and Food Habits of Captive-reared Great Horned Owls. (P. Beaver, editor). Pp. 104-108 in Wildlife Rehabilitation, Vol. 2. National Wildlife Rehabilitators Association: St.Cloud, MN.
Abstract: Captive-reared great horned owls (Bubo virginianus) were released and monitored using radiotelemetry to determine dispersal patterns, food habits, and survivorship. After release, the owls remained in the vicinity of the release site. The most distant radiolocation was 0.5 km. Initially, released owls would alight near any human that approached the release site and beg for food. This behavior decreased over time, but the owls never acquired a fear of man. The released owls readily adapted to hunting and capturing wild prey. Based on observed feeding, released owls captured variety of prey, but a majority of the diet was muskrat (Ondatra zibethicus). For future owl rehabilitation, we suggest minimum human contact during rearing and release at a site with little human disturbance.
Ludwig, D. R., & B. Ferguson. 1991. Post-release Behavior of Captive-reared American Robins (Turdus migratorius). (D. R. Ludwig, editor). Pp. 193-205 in Wildlife Rehabilitation, Vol. 9. National Wildlife Rehabilitators Association: St. Cloud, MN.
Abstract: The post-release behavior of young, captive-reared American robins (Turdus migratorius) was examined and compared with wild-reared young. In this experiment, late nestling and early fledgling robins raised until fully feathered were color banded and released. Site fidelity, as determined by visual search, lasted a mean time of 11.1 days (range 1-18). The behavior of captive-reared robins was not statistically different from wild juvenile robins observed at similar times in the same area. Perching in trees and sitting quietly on the ground were the most frequently observed behaviors.
In a second experiment, 10 juvenile robins were outfitted with radio-transmitter backpacks and observed after release. Observed behavior of these birds was not statistically different from the behaviors of juvenile wild robins. Percent frequency of behaviors most often observed were perching or standing quietly, 68%; hopping,10%; and vocalization, 9%.
Ludwig, D. R., & S. M. Mikolajczak. 1984. Post-release Behavior of Captive Reared Raccoons. (P. Beaver, editor). Pp. 144-154 in Wildlife Rehabilitation, Vol. 3. National Wildlife Rehabilitators Association: St. Cloud, MN.
Introduction: Wildlife rehabilitators often debate the value and quality of rearing systems and the quantity of human support appropriate for captive-rearing of birds and mammals. When establishing a rearing program, attention needs to be given to a mammal’s physical and behavioral development, and to the conditions that approximate a normal physical and social environment. Willowbrook Wildlife Haven’s rearing program attempted to match and foster the normal sequence of behavioral development and physical growth.
This study monitored the post-release behavior and survival of raccoon cubs (Procyon lotor) released from a minimum contact captive rearing program. Answers were sought to the following questions: How does the post-release behavior of captive-reared cubs compare with the behavior of wild-reared raccoons? Are many of the behaviors related to the survival of young raccoons learned from the adult female? Do captive-reared raccoons survive after release?
Odell, C. H. (1983). Radio Telemetry Tracking of Captive Reared Coyotes. (P. Beaver, editor). Pp. 108-115 in Wildlife Rehabilitation, Vol. 2. National Wildlife Rehabilitators Association: St. Cloud, MN.
Purpose: WRT/UNL radio telemetry tracking study of WRT captive reared coyotes had a two-fold purpose:1. To see if the WRT methods of hand rearing coyotes were actually effective in rearing coyotes that could successfully adapt to the wild; and, 2. If they did adapt, would these captive reared coyotes become a nuisance to Nebraska?
Odell, C. H. (1984). Selection of Release Sites and Post-release Findings on Five Hand-reared Bobcats. (P. Beaver, editor). Pp. 155-162 in Wildlife Rehabilitation, Vol. 3. National Wildlife Rehabilitators Association: St. Cloud, MN.
Introduction: On 21 September 1982, five (2M-3F) three-week old bobcats (Felis rufus) were presented for rehabilitation to the Wildlife Rescue Team (WRT) in Lincoln, Nebraska. They had been taken illegally from an abandoned barn south of Culbertson, Nebraska, on 12 September, three days before their eyes opened. They later were confiscated by the Nebraska Game Parks Commission and the men involved were fined $500 (payable to WRT) by the courts.
Bobcats had not been hand-reared and released in Nebraska by WRT or anyone else as far as is known. Current methods of rearing bobcats were reviewed with rehabilitators in other states, and they recommended minimal human contact, road-killed and live prey foods, and some “behavior modification” techniques. Despite minimal handling in captivity, the cats appeared habituated to humans in varying degrees ranging from ‘wary’ to ‘highly habituated.’ The males appeared more habituated than the females. Ideal release sites in which hand-reared predators cannot reach a human habitation within their furthermost range are seldom available in agricultural Nebraska. It was decided by the Nebraska Game Parks Commission that all five bobcats should be released, including the male cat who was least adept at killing, least dominant among littermates, and who appeared highly habituated to humans in captivity.
Successful Wildlife Rehabilitation - Stories on Band Returns
Banding of rehabilitated wildlife can and has proven that many species survive post release and return to normal behaviors, such as successful breeding and migration.
Great Blue Heron
(story text from Lindsay Wildlife Museum’s website (http://www.wildlife-museum.org)
On July 23, 1996 a hatching year great blue heron was found tangled in fishing line with fishing hooks embedded in its wing and brought to Lindsay Wildlife Museum. The bird was stabilized and treated for puncture wounds. The next day the bird was transferred to the International Bird Rescue Research Center's aquatic bird rehabilitation facility in Berkeley, CA. The bird was put on a regimen of antibiotics and treated for its wounds. Its recovery was quick and the bird did well. On July 29, 1996 the bird was banded, number 0977-04747, and released in the Suisun Marsh. Twelve years later on May 28, 2008, the same great blue heron, now an adult but still wearing band number 0977-04747, was again found entangled in fishing line and fish hooks and was captured at a marina in Oakley, CA. The bird was taken to Lindsay Wildlife Museum who, again, stabilized it and removed the fish hooks and line that were tangled around its wing and leg. The bird was then transferred to IBRRC's new facility in Cordelia, CA. As before, it was treated for its wounds, held a week or so and on June 5, 2008 it was released healthy and strong back into the Suisun Marsh. California has a number of prestigious wildlife rehabilitation organizations that remain open 375 days a year to provide shelter and state of the art care for native wildlife in need of care. Lindsay Wildlife Museum and IBRRC are two of those organizations and are considered leaders in the unique field of wildlife rehabilitation. Both organizations have worked in tandem for years to support each to provide the best care for local wildlife. IBRRC specializes in aquatic bird rehabilitation and has specialized facilities to achieve this. Lindsay Wildlife Museum cares for all other species of native wildlife including raptors, passerines, terrestrial mammals and reptiles. When IBRRC receives an owl or occasional mammal for care, they send them to the museum for rehabilitation. In turn, the museum sends IBRRC the aquatic birds that can benefit from their specialized facility. Together we have helped hundreds of animals by cooperating with each other and putting the needs of the animals first. Great blue heron, band number 0977-04747, is a testament to this important relationship and the dedication of these two organizations.
To add your rehabilitation success story that includes federal band return information please contact NWRA’s post-release studies committee chair January Bill at JanuaryBill@hotmail.com
Wildlife Rehabilitation Organizations doing Post-release Studies
Below is a list of wildlife organizations participating in wildlife rehabilitation research and links to their websites:
Tristate Bird Rescue & Research, Inc.
If you are interested in sharing your research projects please contact NWRA’s Post-release study committee chair January Bill: JanuaryBill@hotmail.com
Future NWRA Post-release Study Research Mentorship Assistance
In an effort to promote and support research through National Wildlife Rehabilitators Association members, one of the Post-release Study Committee’s objectives is to develop and provide Research Mentorship assistance with the following goals: